SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'df9329e2ca839e75df9c50bd8b296fa87a96434915621757f402e2f60f669c14' 
  AND token = 'dnYONN5gTqlpKyNq9Djde+/LFTJxvMv4FnwO4JoQrG4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}